Inverted battles

This is only the very beginnings of adding in a new clause for inverted battles.  I followed the format of the other clauses.  I am sure there is a lot that is missing but at the very least wanted to start it so it could get finished.  Also I am not around to finish it for a little bit if anyone wants to pick up the branch >.>

Inverted battles are a new thing in gen 6 in which the type effectivenesses are switched.  Super effective becomes not very effective and immunity becomes normal damage.